This invention relates to a gas-blast electric circuit interrupter of the puffer type and, more particularly, to an interrupter of this type in which the force required from an opening operator for operating the puffer device and separating the contacts of the interrupter during high-current interrupting operations is reduced.
The usual puffer-type circuit interrupter comprises a puffer device that is operated during an interrupting operation to compress arc-extinguishing gas, which is subsequently directed into the arcing zone to aid in arc extinction. In the typical puffer-type circuit interrupter, most of the force for operating the puffer device is derived from the same operator that is used for separating the contacts of the interrupter during the interrupting operation.
A problem usually encountered in such an interrupter is that the high-pressure arcing products produced during a high-current interruption act to oppose operation of the puffer device and to oppose separation of the contacts. More specifically, if the puffer device of such an interrupter comprises a piston positively coupled to the movable contact rod, then the high-pressure arcing products can develop opposing pressures ahead of the piston which can interfere both with operation of the piston and with opening of the contacts at the desired high speeds. One way of overcoming these opposing pressures is to provide an opening operator for the contacts and piston having a very high force output. Such an operator, however, can be quite expensive.